This disclosure relates to a gas turbine engine. In particular, the disclosure relates to cooling features and an example core manufacturing process that produces a core providing such features.
Components, such as airfoils, particularly those used in a hot section of a gas turbine engine, incorporate internal cooling features. Current airfoil manufacturing techniques limit possible cooling configurations. Typically, the airfoil is cast within a mold having at least first and second portions secured to one another to define an exterior airfoil surface. The core structure used to form the impingement holes and cooling passages must be retained between the mold portions, which limit the location and configuration of the core, which is quite fragile. The core is typically assembled from multiple elements constructed from different material. The elements are glued to one another through a painstaking assembly process, which may result in scrapped cores.
Film cooling holes are provided at various locations on the airfoil to supply cooling fluid to the exterior airfoil surface. One type of film cooling hole geometry extends from an inlet passage that communicates with a cooling passage to an outlet that terminates at the exterior airfoil surface. The outlet may be diffuser shaped, if desired. Using traditional film cooling hole forming methods, such as laser machining, electro discharge machining, or drilling, the inlet and outlet passages must be generally coaxially aligned with one another.